1. Technical news:
· The most serious constraint for experiments on HRS lately was the condition of the RFQ. The exact cause of sparking has been identified after opening and has been fixed.
· During the weekend there was a failure of the cooling system of the GPS target station. After efforts during long hours by Erwin, assisted the users (filling the reservoir manually) and the cooling piquet the problem was fixed. It coincided with vacuum problems in the PS which required stopping also the PSB beam. Both the cooling and the protons were recovered at the same time to allow the users on GPS to continue their work. This target unit has already survived 4 target- and line-heating cuts.
· The robot handling the targets at GPS got stuck due to a problem with one of the shelf slots for used targets. The robot requires recalibration by the manufacturer which is due this week. Only after the manipulation it will be clear whether more interventions are required.
· As mentioned 2 weeks ago, the recovery time of HT2 HV power supply was very long and occasionally the voltage was unstable. It was found that the HV was being modulated 37uA after the proton-pulse arrival. The timing was now corrected and HT2 functions normally.
· Currently REX is moving towards optimal operation. It is planned to introduce more powerful pumps in the RF section in order to avoid charge-exchange losses of highly charged beams. The situation with the delivery of liquid He is also improving somewhat.
2.Physics and schedule
· Last Wednesday-Friday morning at HRS ISOLTRAP studied laser-ionized202Pb and surface-ionized 202Tl, which might be candidates for neutrino-mass determination. The reached precision of the Q-value might be insufficient.
· In parallel GPS was used for collections of rare-earth beams for semiconductor and biological (cancer therapy and PET imaging) studies.
· Over the weekend GPS was used by COLLAPS to determine the magnetic moment of 140Pr, whose production rate turned out to be too week. Instead several other Pr isotopes were investigated.
· On Monday, RILIS delivered first laser-ionized beams of radioactive Dy at ISOLDE. The lasers improved production by a factor of 7. ISOLTRAP used the opportunity to measure 168Dy, but the yield was still too low and contaminants too strong.
· Upcoming runs: WITCH with 35Ar and MINIBALL with 140Nd.
· Draft of the second part of the schedule has been discussed with the technical group and experiment responsible. The final version should be out early next week.
3.Safety
· New radiation-monitor display (RAMSES) is now available at ISOLDE. It is quite intuitive in use, but we are promised a quick explanation by RP.
· We were missing a 137Cs source. It was eventually found, but the users have not marked that they had taken it and they forgot to give it back. Please return the sources after use!
· The export of radioactive samples is obviously person dependent and despite the positive experiences from a couple of weeks ago was again problematic.
4. Seminars:
· On Friday 24 June at 11 am there will be a seminar by Mr. Markus Jaeger (University of Leipzig) about “DIGIPAC - a real time digital Perturbed Angular Correlation spectrometer”.
· For more information and links to the slides please visit the ISOLDE - seminars page.
Minutes by MK and DTY